ABSTRACT A recently-defined subtype of colorectal cancer (CRC), ?serrated CRC?, is thought to arise from a distinct developmental pathway involving the progression of serrated polyps through accumulation of aberrant methylation and specific somatic mutations in BRAF or KRAS. Despite growing evidence that serrated CRC is a particularly aggressive subtype, little is known as to what factors may predispose individuals to serrated CRC, and the clinical implications of this disease subtype have not been well-characterized. Therefore, our parent award goals are to compare serrated CRC to non-serrated CRC with respect to 1) germline genotype, 2) personal and histopathological features, and 3) prognosis. This research will provide important information on common genetic variants that predispose individuals to serrated CRC, and on the clinical presentation and outcomes of this high-risk CRC subtype. In this application, we seek to enhance the value of our ongoing parent project by contributing data to the NCI-supported Cancer Epidemiology Data Repository (CEDR), a centralized, controlled-access database, where Investigators can deposit individual-level de-identified observational cancer datasets. Modeled after successful NIH-supported data repositories, CEDR will enable broad collaboration, exploration of new hypotheses, development of innovative statistical methodologies, and replication of published findings. We will provide data from the parent project to CEDR across several different categories: histopathological, epidemiologic, clinical, outcomes, and tumor molecular data. This data may be accessed and further analyzed in conjunction with genomic data collected in our study, which will be available in dbGaP. This supplement will increase utilization of the resource by making well-annotated data available to a wider range of scientists, accelerate scientific discovery and increase opportunities for collaboration to provide new clues to cancer etiology, determine risk factors, and improve cancer survivorship.